The goal of this Phase IIB SBIR application is to test the Sentien cellular bioreactor product (the Sentinel) in a first-in-man study to assess safety and preliminary efficacy. Fifteen post-cardiac surgery patients that are diagnosed with acute kidney injury and indicated for dialysis will be enrolled and connected to the Sentinel containing one of three escalating doses of cells, n=5 per dose: 250M, 500M and 1000M. Primary endpoints involve measures of safety, and patient samples will be taken for analysis by Sentien to evaluate possible trends in efficacy. The project specific aims are: (1) conduct a single- center, open-label, dose escalation safety study of the Sentinel in cardiac surgery patients diagnosed with AKI and indicated for CVVH; (2) measure experimental urine biomarkers for preliminary monitoring of device efficacy; and (3) profile the inflammatory response pathway in paired testing of patient blood. The deliverables of this project will be (1) a record of adverse events with the Sentinel compared to historical controls; and (2) preliminary efficacy data as measured by urine biomarkers, serum cytokines and ex vivo blood mononuclear cell assays.